Janssen's Tremfya (guselkumab) has been approved in the US as the first selective interleukin (IL)-23 inhibitor for adults with active psoriatic arthritis (PsA).

The condition is a chronic progressive disease characterised by painful joints and skin inflammation, for which there is currently no cure.

Tremfya is the first treatment approved for active PsA that selectively inhibits interleukin (IL)-23, a naturally occurring cytokine involved in normal inflammatory and immune responses.

The drug's approval rides on data from the two pivotal Phase III clinical trials, DISCOVER-1 and DISCOVER-2, which evaluated its efficacy and safety when administered by subcutaneous injection in adults with active PsA compared to placebo.

The results showed that a significant percentage of patients treated with Tremfya reached the studies’ primary endpoint of ACR20 at 24 weeks, with 52% and 64% of patients achieving an ACR20 response compared to 22% and 33% in patients treated with placebo in DISCOVER-1 and DISCOVER-2, respectively.

“Psoriatic arthritis is a complex multi-faceted disease and, for many patients, additional biologic options are very much needed,” said Philip J. Measei, DISCOVER-2 lead study investigator, director of Rheumatology Research at the Swedish Medical Center/Providence St. Joseph Health and Clinical Professor at the University of Washington School of Medicine in Seattle, WA.

The approval “is exciting for both patients and their physicians, as there is now a new approach available to help manage the symptoms of active psoriatic arthritis that patients face day to day.”